If you've played Ocarina of Time, you've seen this little fairy fucker. Still don't recognize her? Well:

Remember that shit? Well, that's Navi saying it.

Well, despite that shit talk I just said above, I don't hate Navi. While yes, she is annoying as hell (I would say more annoying then Midna sometimes (GASP)), at least she CARES about you and your quest to save Hyrule. It's also nice that she says "Watch out!" because it shows she's looking out for you. How nice of her!

How does Navi relate to Midna? They're there with you the ENTIRE game.  From the beginning to end. Well, except Midna's not there at the very beginning. Just when you turn into Wolf Link (who, by the way, is completely useless.) Man. I was enjoying the game so much until that part. It's not even funny. I paid a ton of money for the GameCube version and Midna ruined the purchase for me. I want my money back.

Oh, and also, Navi gives you useful info sometimes. Midna just calls you an idiot.